During the past few years substantial evidence has correlated anomalous spacecraft behavior with differential high voltage charging due to magnetospheric plasma particle interaction. Spacecraft charging effects range from the nuisance category of telemetry anomalies through antenna pointing errors that have resulted in a temporary loss of communications. In order to prevent these undesirable effects, it is necessary to prevent the build-up of large potential gradients on dielectric surfaces, because the large potential may arc to a ground point. The potential build-up on a dielectric surface in a given energetic charged particle environment is directly proportional to the surface resistivity of the exposed dielectric. Furthermore, the energy available in the discharge of such surfaces is proportional to the square of surface resistivity. Since surface resistivity of many dielectrics used in spacecraft construction are typically in the range of from 10.sup.12 to 10.sup.17 ohms per square, the amount of energy which can be coupled into sensitive electronic components can be substantial. Discharge energies of many millijoules are possible. Thus, a means for providing low rate discharge of such surface charging is a preventive necessity against potentially harmful electrostatic discharges.
Most conductive coatings in the prior art were applied either by vacuum deposition or as conductive paint. The deposition of a metal from the vapor form in vacuum is not suitable for many spacecraft assemblies. Furthermore, it is not readily repairable, should there be a problem. With respect to conductive paints, the resistivities are not uniform or repeatable. Furthermore, conductive paint is very much heavier. Thus, there is need for a proper electric discharge coating.